21415020877 has 4 divisors (see below), whose sum is σ = 21571335036. Its totient is φ = 21258706720.

The previous prime is 21415020871. The next prime is 21415020883. The reversal of 21415020877 is 77802051412.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21415020871) and next prime (21415020883).

It can be written as a sum of positive squares in 2 ways, for example, as 7839508681 + 13575512196 = 88541^2 + 116514^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21415020877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21415020871) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78156874 + ... + 78157147.

It is an arithmetic number, because the mean of its divisors is an integer number (5392833759).

Almost surely, 2^21415020877 is an apocalyptic number.

It is an amenable number.

21415020877 is a deficient number, since it is larger than the sum of its proper divisors (156314159).

21415020877 is a wasteful number, since it uses less digits than its factorization.

21415020877 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156314158.

The product of its (nonzero) digits is 31360, while the sum is 37.

The spelling of 21415020877 in words is "twenty-one billion, four hundred fifteen million, twenty thousand, eight hundred seventy-seven".